Tool for electrolytically honing spherical surfaces

ABSTRACT

A TOOL FOR HONING SPHERICAL SURFACES BY ELECTROLYTIC ACTION INCLUDES A CONCAVE SPHERICAL SURFACE CONNECTED AS ONE ELECTRODE WHILST THE SPHERICAL SURFACE TO BE HONED IS CONNECTED AS THE OTHER ELECTRODE. THE SPHERICAL SURFACE OF THE TOOL IS ENCIRCLED BY A RING MEMBER FACED WITH AN ANBRASIVE SURFACE AND THE LATTER LIES WITHIN THE IMAGINARY SURFACE OF THE SPHERE. A SENSING NOZZLE IS DISPOSED ON THE   COMMON AXIS OF THE TOOL AND SPHERICAL SURFACE OF THE WORKPIECE.

1973 A. GROSSEAU 3,730,870

TOOL FOR ELECTROLYTICALLY HONING SPHERICAL SURFACES Filed June 29, 1971 3,730,870 TOOL FOR ELECTROLYTICALLY HONING SPHERICAL SURFACES Albert Grosseau, Chaville, France, assignor to Societe Anonyme Automobiles Citroen, Paris, France Filed June 29, 1971, Ser. No. 157,980 Claims priority, application France, July 3, 1970,

Int. Cl. B23p 1/10; C23b 5/72; B011: 3/00 US. Cl. 204224 3 Claims ABSTRACT OF THE DISCLOSURE A tool for honing spherical surfaces by electrolytic action includes a concave spherical surface connected as one electrode whilst the spherical surface to be honed is connected as the other electrode. The spherical surface of the tool is encircled by a ring member faced with an abrasive surface and the latter lies within the imaginary surface of the sphere. A sensing nozzle is disposed on the common axis of the tool and spherical surface of the workpiece.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to a tool for honing spherical surfaces.

(2) Description of the prior art An electro-chemical method of honing has been pro posed in which an electrolyte is passed between the workpiece, which forms the anode, and a tool, which constitutes the cathode andis located very close to the workpiece.

The application of this method to the honing of spherical surfaces presents problems. In the first place, it is difiicult to maintain the correct spacing between tool and workpiece, especially when the tool has to work round the outline of the material in such a manner as to preserve the existing axes. Tubular honing tools hitherto used for the purpose are not efficacious, because, owing to their wear, they do not enable the necessary constant spacing to be kept. Finally, the violent throw-off of electrolyte makes it difficult to insert any gauging instrument.

An object of the present invention is to provide an improved tool for honing spherical surfaces electrochemically.

SUMMARY OF THE INVENTION According to the present invention there is provided in a tool for the electro-chemical honing of spherical surfaces, means defining a part-spherical face forming an electrode, means defining an abrasive ring having a working surface adjacent the edge of the part-spherical face,

and a sensing blower nozzle, which lies in the longitudinal centre line of the tool and is arranged to be connected to a measuring device.

When the tool is in use, both it and the spherical face that is to be honed are rotated and the abrasive surface is brought into contact with the latter. The purpose of the abrasive surface is threefold: it plays a part in the honing by forming a stop for the face of the workpiece; it determines the spacing between the latter and the spherical face of the tool, these constituting the two electrodes; and finally it provides a reference point or surface for gauging purposes.

As the abrasive ring is only partly responsible for the honing, it wears very little; and the variation in radius of the surface being honed is very small as the honing proceeds; hence, the spacing between the two electrodes remains substantially constant. Finally, the nozzle lying in 3,730,870 Patented May 1, 1973 the tool axis is well clear of the zones of electrolyte pressure and thus permits accurate and reliable gauging measurement.

BRIEF DESCRIPTION OF THE DRAWING An embodiment of a honing tool in accordance with the invention will now be described by way of example with reference to the accompanying drawing. in which:

FIG. 1 is a longitudinal section of the tool; and

FIG. 2 is an end elevation.

DESCRIPTION OF THE PREFERRED EMBODIMENT The embodiment of the tool is intended for honing a workpiece 1 having an at least part-spherical surface. This tool comprises a body 2, the forward end of which terminates in a concave part-spherical face 2a, having substantially the same radius as the spherical convex surface to be honed. A diamond-faced ring 3, with crenellations 3a, is mounted on the forward end of the tool, a ring of insulating material being interposed at 4, and is held in place by electrically insulated screws 5. The diamondfaced part of the ring 2 lies inside the imaginary sphere defined partly by the face 2a, thereby maintaining between the latter and the face 1 a gap sufiicient to allow electrochemical honing to take place. This diamond-faced part of the ring may be, for example, frusto-conical in shape. The space 6 is substantially of uniform thickness and varies little as honing proceeds.

Fixed in the body 2 is a blower nozzle 8, in communication with an axial passage 9. This body 2 also contains one or more passages 10, opening into the spherical face 2a, their purpose being to admit electrolyte to the gap 6, as well as passages at 11 for the escape of the air blown in.

Finally, the body 1 carries two rotating connectors, 12 and 13, with which the axial passage 9 and the passage or passages 10 can communicate respectively with a compressed-air feed pipe 14, fitted with a flow regulator, and an electrolyte feed pipe 15.

In operation, the body 2 and the spherical face are connected respectively to the cathode and anode of an electricity supply. The face 1 of the workpiece is rotated by a headstock drive (not shown), the axis of rotation 16 of which is inclined in relation to the axis of rotation 17 of the tool. The tool itself is loosely or rigidly mounted on a rotating spindle (likewise not shown) and is brought to bear on the face 1 by movement along the axis 17.

The electrolyte, admitted through the feed pipe 15, arrives by way of the passage or passages 10 at the face 2a and fiows through the gap 6, carrying with it the hydroxides brushed away by the abrasive ring 3; it is evacuated through the crenellations 3a of that ring.

As the honing progresses, the nozzle 8 approaches the face 1, so that the back-pressure rises in the pipe 14; when honing is complete, the hone having reached its reference position, the pressure in the pipe reaches a predetermined value, by virtue of which it operates a pneumatic control (not shown), causing the spindle that carries the tool to withdraw. The spherical surface obtained when honing is completed, is thus determined by the relative positions of the nozzle 8 and the abrasive surface 3.

What I claim:

1. In a tool for the electro-chemical honing of spherical surfaces,

means defining a part-spherical face forming an electrode,

means defining an abrasive ring having a working surface adjacent the edge of the part-spherical face, and

a sensing blower nozzle, which lies in the longitudinal centre line of the tool and is arranged to be connected to a measuring device.

3 4 2. A tool as claimed in claim 1, in which the Working FOREIGN PATENTS face of the abrasive ring lies inside the imaginary sphere 1 294,824 4/ 1962 France defined by the said part-spherical face forming an elec- I g 1 I d l z h. h h M JOHN H. MACK, Primary Examiner too ascaime incalm ,lnwlc tewor mg 5 face of the ring is of frusto-conical shape. VALENTINE Asslstant Exammer References Cited UNITED STATES PATENTS 204-225, 277

3,442,784 5/1969 Wieck 204-224 X 

